Missing "/" for orgPath element when Including file at root of project

[AnthonyCogworks]

How to reproduce.

1. Include a file at the root of the project.
2. Run the grunt umbraco packaging
3. Try to install the package manually - Umbraco throw a 500. It occurs for all umbraco v7+.

Reason: orgPath is empty for files at the root:

`

	<file>
		<guid>myfile.html</guid>

		<orgPath></orgPath>

		<orgName>myfile.html</orgName>

	</file>

`

Fix: Files added at the root need a slash:

`

	<file>

		<guid>myfile.html</guid>

		<orgPath>/</orgPath>

		<orgName>myfile.html</orgName>

	</file>

`

The specific error is this:
2017-07-03 10:54:42,824 [P6248/D2/T34] ERROR umbraco.cms.businesslogic.packager.Installer - Error importing file E:\Temp\UmbracoCms.7.6.3\App_Data\97508966-55a6-4fbd-ba69-35d4df4ef3dd.umb
System.IndexOutOfRangeException: Index was outside the bounds of the array.
at umbraco.cms.businesslogic.packager.Installer.GetFileName(String path, String fileName)
at umbraco.cms.businesslogic.packager.Installer.LoadConfig(String tempDir)
at umbraco.cms.businesslogic.packager.Installer.Import(String inputFile, Boolean deleteFile)
2017-07-03 10:54:42,824 [P6248/D2/T34] ERROR Umbraco.Web.WebApi.Filters.FileUploadCleanupFilterAttribute - Could not acquire actionExecutedContext.Response.Content
System.NullReferenceException: Object reference not set to an instance of an object.
at Umbraco.Web.WebApi.Filters.FileUploadCleanupFilterAttribute.OnActionExecuted(HttpActionExecutedContext actionExecutedContext)